Hardcore realism mode:
Press UP, DOWN, LEFT, RIGHT, WHITE, UP, DOWN at the main menu. Alternately, get
a 100 point rating on a track to unlock the hardcore realism mode option for
that track.

Shoot paintballs:
Select single race or head-to-head mode. Press UP, DOWN, LEFT, RIGHT, WHITE, UP,
UP at the "Race Day" screen. Use your horn (press UP) to shoot a paintball. This
also works in two player mode. Alternately, select practice mode and press UP,
DOWN, LEFT, RIGHT, WHITE, DOWN, DOWN to enable paintballs.

View credits:
Press UP, DOWN, LEFT, RIGHT, WHITE, LEFT, LEFT at the main menu.

High suspension:
Press UP, DOWN, LEFT, RIGHT, WHITE, LEFT, RIGHT at the main menu.

Mini cars:
Press UP, DOWN, LEFT, RIGHT, WHITE, DOWN, UP at the main menu.

Wire frame cars:
Press UP, DOWN, LEFT, RIGHT, WHITE, RIGHT, LEFT at the main menu.

Richard Petty:
Successfully complete all Heat challenges with a bronze or higher rating.